This document gives a comprehensive overview of the urban ILM (Innovatief Lucht Meetsysteem, English: Innovative Air Measurement System) that has been installed in the City of Eindhoven under the AiREAS initiative. Here, the intention is to provide the necessary scientific and technical details so that a user can understand the provenance of the data outcome. The social rationale for such a system was outlined in Chap. 2 of this document. Technically, the use of modern, low-cost sensors offers the possibility of obtaining new scientific insights by measuring several air quality variables at a finer temporal and spatial resolution than previously possible. Conventional networks typically measure at only one or two locations in cities the size of Eindhoven, where the temporal resolution tends to be one sample each 24 h (or even coarser). In brief, the ILM consists of 35 Airboxes which have been installed at various locations throughout Eindhoven. These boxes contain communication and data-logger devices, as well as sensors that measure various air quality variables (particulate matter, ultrafine particle counts, ozone, nitrogen dioxide) and meteorological variables (temperature, relative humidity). These variables are measured every 10 min. Following calibration, these are made available online in near-real time. A complete archive is also made available online. Particulate matter (specifically PM10 and PM2.5), ozone (O3) and nitrogen dioxide (NO2) are the most important air quality variables to be routinely measured. Ultra-fine particles are of increasing interest, but are not routinely measured. Hence, they were included in the set of measured variables. Although the ILM is low cost compared to conventional sensors, there are still cost constraints. The budget allowed for the installation of 35 Airbox sensor units, each measuring PM and O3. NO2 is measured at five locations, although there is a plan to expand this to 25 locations (i.e., 20 extra sensors) during 2015. UFPs are measured at six locations. In order to measure the air quality variables at 35 locations, affordable measurement devices were needed that could easily be located and relocated within an urban setting. As accurate sensors for ambient air were not commercially available, state of the art sensors for PM, NO2 and O3 were modified to comply with the required specifications. In this survey, we first provide an overview of the variables that are measured (Sect. 3.2). The technical equipment and instrumentation are then described (Sect. 3.3), followed by a discussion of data quality (Sect. 3.4). The choice of locations for spatial sampling is discussed in Sect. 3.5, followed by a discussion of data management (Sect. 3.6). Some initial results are presented (Sect. 3.7), followed by a list of projects based on the ILM (Sect. 3.8). Each section closes with a sub-section labelled experiences and recommendations.߿ݠThis outlines our experiences to date and gives recommendations for the future. Some of these recommendations are concrete and have been agreed upon. Others recommendations still need to be finalized or further discussed.